培养大鼠星形胶质细胞牵张损伤后超微结构的变化

目的研究体外培养星形细胞牵张损伤后超微结构的变化。方法取新生1~2 d大鼠的皮层细胞原代培养,经纯化后传代培养于乳胶膜培养皿中。采用计算机控制的牵张损伤装置,分别以50、150、250 kPa压力牵张损伤培养于乳胶膜上的大鼠皮层星形胶质细胞。用3%戊二醛固定后,行扫描电镜和透射电镜观察。结果当用50 kPa驱动压力进行牵张损伤时,细胞结构即有明显破坏,表现为细胞间隙增宽,部分胞体和突起被撕裂;以50 kPa牵张损伤后1 h,透射电镜下可见线粒体肿胀、嵴减少;损伤后6 h可见线粒体致密、细胞器减少等。当牵张应力增大,星形细胞损伤程度加重,细胞器明显减少,线粒体空泡化,微丝、微管明显减少,直至水样胞质或致密胞体。结论较小的应力即可致星形细胞紧密连接的破坏和超微结构的改变,可能与脑外伤后产生广泛的脑水肿有关。

Ultrastructural features of cultured rat cortical astrocytes with stretch-induced injury

Objective To investigate the changes of ultrastructural features of cultured rat cortical astrocytes after stretch-induced injury. Methods Rat cortical astrocytes isolated from 1- to 2-day-old rats were cultured till confluency, and then plated in tissue culture wells with flexible silastic bottom after purification. A computer-controlled device was used to produce stretch-induced injury in the astrocytes with the imposed pressure of 50, 150, and 250 kPa repsectively, followed by observation of the ultrastructural changes in the astrocytes with light and electron microscopy. Results Obvious ultrastructural destruction of the astrocytes occurred when the imposed stretch pressure was 50 kPa, and scanning electron microscopy demonstrated increased intercellular space and laceration of the cell body and its processes. Transmission electron microscopy revealed mitochondria swelling 1 h after stretch-induced injury and 6 h after the injury, vacuolar degeneration of the mitochondria occurred. Increased stretch pressure caused further decrease in the amount of glial filaments and densification of astrocytes. Conclusions Stress, even at a relatively small scale, can cause disruption of intercellular juncture and ultrastructural change of the cultured astrocyte, which may be related with extensive brain edema after traumatic brain injury.